Feeding system

ABSTRACT

A feeding system for connecting a humidifier to a reservoir comprising, a first elongated conduit for feeding water from the reservoir to the humidifier, a second elongated conduit alongside the first conduit for passing air from the humidifier to the reservoir, with an upper end of the first and second conduits being connected in fluid communication to the reservoir. The conduits are connected to the humidifier with a lower end of the first and second conduits located inside the humidifier, and with the lower end of the first conduit being located adjacent the lower end of the second conduit.

This is a continuation of application Ser. No. 087,135, filed Aug. 19,1987, now abandoned, which is a continuation of Ser. No. 747,219, filedJune 21, 1985, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to a liquid feeding system for ahumidifier.

Humidifiers in a breathing circuit for a patient are known. In suchsystems, a sterile liquid is placed in the humidifier with the liquidbeing heated, and an air mixture is passed from a ventilator through theliquid in order to heat and humidify the air mixture, and the resultingair mixture is passed to the patient. However, during use of thehumidifier the liquid is utilized to humidify the air mixture, and it isnecessary to periodically replenish the liquid in the humidifier. In thepast, the humidifier was normally taken apart, and additional liquid waspoured into the humidifier. It has been found that this procedure isinconvenient, and poses the possibility of contaminating the liquid dueto handling of the liquid. Other procedures are to pour water throughone of the ports of a cap for the humidifier. Alternatively, water canbe fed from a suspended flexible solution bag through a special set. Thedisposable set, which is manufactured by a company, consists of a teeadapter which fits over the cascade outlet. The patient hose isconnected to the perpendicular leg of the tee and the remaining leg isconnected to the solution bag via a vinyl tube. Water is deliveredthrough the adapter to the cascade by opening a tube clamp whenrequired. Although the filling process is simplified it is still manualrequiring frequent attention. Further, versions of the humidifier offera special port for inserting a water feed system. The system,manufactured by a company, is composed of a suspended glass bottle whichfeeds the water through a large bore tube to a valve assembly which ispositioned within the cannister. The valve is automatically closed whenthe water level reaches the required height. Although the systemcontinuously feeds water as needed, the set-up must be cleaned andsterilized for re-use.

SUMMARY OF THE INVENTION

A principal feature of the present invention is the provision of afeeding system for connecting a humidifier to a reservoir.

The feeding system comprises first elongated conduit means for feedingwater from the reservoir to the humidifier, second conduit meansalongside the first conduit means for passing air from the humidifier tothe reservoir, and means for connecting an upper end of the first andsecond conduit means in fluid communication to the reservoir. The systemhas means for connecting the conduit means to the humidifier with alower end of the first and second conduit means located inside thehumidifier, and with the lower end of the first conduit means beinglocated adjacent the lower end of the second conduit means. The systemhas an elbow connected to the first and second conduit means and havinga hollow first part surrounding and spaced from the first and secondconduit means, and a hollow second part in fluid communication with thefirst part and extending at an angle to the longitudinal axes of thefirst and second conduit means. A lower end portion of the first andsecond conduit means extends through and from the elbow to a locationinside the humidifier.

A feature of the present invention is the outside diameter of the firstconduit means is substantially smaller than the outside diameter of thesecond conduit means in order to make the first conduit means as smallas possible and the second conduit means as large as possible withoutobstructing passage of humidified air through the elbow to the patient.

Another feature of the invention is the lower end of the second conduitmeans is formed at an angle relative to the longitudinal axis of thesecond conduit means in order to break surface tension and drain a lowerpart of the second conduit means during use of the system.

Yet another feature of the invention is that at least a portion of thelower end of the second conduit means is located below the lower end ofthe first conduit means to facilitate rapid initial filling of thehumidifier.

Further features will become more fully apparent in the followingdescription of the embodiments of this invention and from the appendedclaims.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a fragmentary plan view of a humidifying system of the presentinvention;

FIG. 2 is a sectional view of a humidifier for the system of FIG. 1;

FIG. 3 is a fragmentary sectional view of a feeding system for thesystem of FIG. 1;

FIG. 4 is a fragmentary perspective view of a lower portion of areservoir for the system of FIG. 1;

FIG. 5 is a perspective view of a clip for the reservoir of FIG. 4; and

FIG. 6 is a perspective view illustrating upper ends of conduits forplacement in a lower part of the reservoir.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIGS. 1-3, there is shown a humidifying systemgenerally designated 10 comprising a ventilator 12 of known type, ahumidifier 14 of known type, a reservoir 16 for retaining sterile water,and a feeding system 18 according to the present invention.

As shown, the humidifier 14 has a bowl 20 to retain a supply of sterilewater W in a lower part thereof, and a lid 22 releasably attached to anupper part of the bowl 20 by suitable means such as threads 24, with thebowl 20 and lid 22 defining a chamber 25. The humidifier 14 also has aheater 26 of known type in order to heat the water W in the humidifier14. The humidifier 14 has an inlet port 28 of an elongated tubularsection 30 with a lower part of the tubular section 30 located beneaththe level of the water W, and with the lower part of the tubular section30 having apertures 32 to permit passage of gas therethrough. Thehumidifier 14 has an annular flange 34 extending from a side of thetubular section 30 toward a central portion of the bowl 20 with an upperwall or sparger plate 36 being located alongside the tubular section 30above the annular flange 34 and having a plurality of relatively smallapertures 38 for a purpose which will be described below. As shown, thesparger plate 36 is located beneath the level of the water W. Thehumidifier 14 also has a tubular section 40 on the lid 22 defining anoutlet port 42.

The system 10 has a corrugated tube 44 connected to an outlet 46 of theventilator 12 to the inlet port 28 of the humidifier 14. In use, theventilator 12 delivers a volume of gas, such as an oxygen mixture, incycles with the pressure and volume being controlled in order tosimulate the normal breathing mechanism of a patient. The gas isdelivered through the tube 44 and tubular secton 30 into the water Wthrough the apertures 32 to a location intermediate the flange 34. Thegas then passes through the apertures 38 of the sparger plate 36 andthrough the water to a location above the level of the water W. Thesparger plate 36 provides improved mixing of the gas with the water, andbreaks up the gas flow to avoid large bubbles. As the gas passes throughthe water W and the sparger plate 36 it is humidified by the water W.Also, the heater 26 heats the water W, and the heated water in turnheats the gas while passing through the water W. The heated andhumidified gas passes along the surface of the water W and through theoutlet port 42 to the patient, as will be further described below.

The reservoir 16 is suspended by suitable means, such as a hook 48,received in an upper ring 50 of the reservoir 16 at a location above thehumidifier 14. The reservoir 16 has an outer wall 52 defining a chamber54 to retain sterile water or liquid L which is fed to the humidifier14, as will be described below. With reference to FIGS. 4 and 6, thereservoir 16 has a pair of lower openings 56 and 58, and a downwardlyextending protuberance 60 adjacent the openings 56 and 58.

With reference to FIGS. 3 and 6, the feeding system 18 of the presentinvention has first water conduit means 62 having an upper end 64connected to the reservoir 16, and a lower end 66 received in thehumidifier 14. The feeding system 18 also has second gas conduit means68 having an upper end 70 connected to the reservoir 16, and a lower end72 received in the humidifier 14. The feeding system 18 has an elbow 74having a hollow first cylindrical part 76 extending around and spacedfrom the first and second conduit means 62 and 68, and a hollowcylindrical second part 78 communicating with the first part 76 andextending at approximately a 90 degree angle to the longitudinal axes ofthe first and second conduit means 62 and 68. The elbow 74 has first andsecond upwardly directed hollow nipples 80 and 82, and third and fourthdownwardly directed hollow nipples 84 and 86, with the first nipple 80communicating with the third nipple 84 and with the second nipple 82communicating with the fourth nipple 86. As shown, the nipples 80-86 arelocated above the first and second parts 76 and 78 of the elbow 74.

The first conduit means 62 has an upper tubular section 88 with a lowerend 90 received on the first nipple 80. The tubular section 88 has anupper end terminating in a spike 92 for connecting the tubular section88 in fluid communication to the reservoir 16 through the opening 58.The tubular section 88 also has an outwardly directed flange 94 adjacentthe spike 92 to limit movement of the tubular section 88 into thereservoir 16. The second conduit means 68 has an upper tubular section96 having a lower end 98 connected to the second nipple 82. The tubularsection 96 has a hollow spike 100 for connecting the second conduitmeans 68 to the reservoir 16 through the opening 56. The tubular section96 has an outwardly directed flange 102 adjacent the spike 100 to limitmovement of the spike 100 into the reservoir 16.

As shown in FIG. 3, the lower ends of the first and second conduit means62 and 68 are defined by a co-extruded double lumen tubular section 104having a first tube 106 of the first conduit means 62 with an upper end108 received on the third nipple 84, and a second tube 110 of the secondconduit means 68 having an upper end 112 received on the fourth nipple86. In use of the system 10, the first part 76 of the elbow 74 isattached to the tubular section 40 of the humidifier 14, and in thisconfiguration, the tubular section 104 extends through the first part 76of the elbow 74 to a location substantially below the elbow 74 into thebowl 20 of the humidifier 14.

As shown in FIG. 3, the outside diameter of the first tube 106 issubstantially smaller than the outside diameter of the second tube 110,with the inside diameter of the first tube 106 being made as small aspossible, and the inside diameter of the second tube 110 being made aslarge as possible for purposes which will be described below. In apreferred form, the internal diameter of the first tube 106 isapproximately 0.080 inches in diameter, the internal diameter of thesecond tube is approximately 0.260 inches in diameter, and the internaldiameter of the first part 76 of the elbow 74 is approximately 0.730inches in diameter which is greater than the width of the tubularsection 104 which is approximately 0.470 inches. Also, the lower end 72of the second conduit means 68 is formed at an angle of less than 60degrees and preferably approximately 45 degrees to the longitudinal axisof the second conduit means 68 for a purpose which will be describedbelow. The lower end of the first conduit means 62 is formed at an angleof approximately 90 degrees to the longitudinal axis of the firstconduit means 62. As shown, the lowermost portion of the angle formedpart of the lower end 72 of the second conduit means 68 is locatedadjacent the lower end 66 of the first conduit means 62, and the lowerend 66 of the first conduit means 62 is preferably located intermediatethe lower and upper portions of the angle formed part of the secondconduit means 68.

In a further description of the use of the system 10, with reference toFIGS. 1-3, a corrugated tube 114 is connected to the second part 78 ofthe elbow 74 and extends to the patient.

When the first part 76 of the elbow 74 is connected to the tubularsection 40 of the humidifier 14, the heated humidified gas passesthrough the outlet port 42, the first and second parts 76 and 78 of theelbow 74 and through the tube 114 to the patient for therapy.

With reference to FIGS. 4 and 5, the system 10 has a clip 116 to retainthe first and second conduit means 62 and 68 to the reservoir 16. Theclip 116 has a first hook portion 118 at one end of the clip 116received on the first and second conduit means 62 and 68 adjacent theflanges 94 and 102. The clip 116 has a second hook portion 120 at theother end of the clip 116 extending partially around the protuberance 60of the reservoir 16. The clip 116 has a central portion 122 connectingthe first and second hook portions 118 and 120. The first hook portion118 may first be secured about the first and second conduit means 62 and68, and the second hook portion 120 may then be secured about theprotuberance 60 of the reservoir 16. In this manner, the clip 116retains the first and second conduit means 62 and 68 in the reservoir 16to prevent accidental pulling out of the first and second conduit means62 and 68 for a purpose which will be described below. The clip 116 maybe made of any suitable material, such as metal.

During use of the system 10, the water W which is utilized to humidifythe gas which passes to the patient reduces the water level in the bowl20 of the humidifier 14 and, in the past, it was necessary toperiodically replenish the supply of water W in the humidifier 14. Theprocedure would normally be carried out by removing the lid 22 from thebowl 20, and pouring water into the bowl 20 to raise the level of waterin the bowl 20. It has been found that this procedure is inconvenient,and also poses the possibility of contamination to the water which ispoured into the bowl 20 during handling. Other methods of filling aredisclosed on page 1.

In accordance with the present invention, the feeding system 18automatically feeds water from the reservoir 16 to the bowl 20 of thehumidifier 14 in order to maintain the desired level of water W in thehumidifier 14. When the level of water W is below the lower end 72 ofthe second conduit means 68, gas passes through the second conduit means68 and bubbles up through the liquid L in the reservoir 16, while waterpasses downwardly through the first conduit means 62 into the humidifier14. However, when the water rises in the humidifier 14 and closes offthe second conduit means 68, the water continues flowing for a time fromthe reservoir 16 through the first conduit means 62 into the humidifier14, and develops a vacuum above the head of liquid L in the reservoir16. In order for the liquid to stop flowing downwardly from thereservoir 16, it is necessary for the vacuum in the reservoir to reach anegative pressure equal to the hydrostatic head in which case the systemis at equilibrium. Meanwhile, the water in the humidifier 14 has closedoff the second conduit means 68, and water starts rising in the secondconduit mens 68. The second conduit means 68 fills with water and thesystem reaches equilibrium.

During further use of the system 10, water is utilized to humidify thegas passing to the patient, and the water level eventually drops belowthe lower end 72 of the second conduit means 68. At this time, surfacetension initially prevents gas from passing up the second conduit means68, but angle formed lower end 72 of the second conduit means 68 breaksthe surface tension in order to drain the second tube 110 of the secondconduit means 68. After the second tube 110 has drained, there exists agreater pressure acting on the lower part of the remaining column ofwater in the second conduit means 68 than its hydrostatic head, suchthat the water flows into the reservoir 16, after which normal flow ofwater begins again through the first conduit means 62, and gas passesupwardly through the second conduit means 68.

In accordance with the present invention, the first tube 106 is made assmall as possible in diameter, and the second tube 110 is made as largeas possible in diameter while minimizing restriction of gas flow throughthe elbow 74 and outlet port 42 to the patient. The first and secondtubes 106 and 110 are made of the desired sizes while permitting waterfeeding of the system 18 from the reservoir 16 to the humidifier 14.

As shown in FIG. 1, the system 18 has a pair of clamps 124 and 126 whichmay be utilized before the initial filling of the humidifier 14, andwhile changing reservoirs 16 to close off the first and second conduitmeans 62 and 68. Of course, the clamps 124 and 126 are open during useof the system to permit passage of liquid and gas through the first andsecond conduit means 62 and 68.

It is desirable to use the feeding system 18 in connection with thereservoir 16 to initially fill the humidifier 14 to the desired level.If the humidifier 14 was filled through the relatively small firstconduit means 62, it would require an extended period of time, such astwenty-five minutes, to reach the desired liquid level in the humidifier14. Thus, it is desirable to initially fill the humidifier 14 throughthe relatively large second conduit means 68, and the liquid exists atthe lower edge of the formed lower end 72 of the second conduit means68, while gas passes through the first conduit means 62. However, if thelower ends of the first and second conduit means 62 and 68 were on astraight slant, the water exiting from the second conduit means 68 wouldbe pulled up into the first conduit means 62 which would slow down andpossibly stop filling of the humidifier 14 since gas would not bepassing up through the first conduit means 62. Hence, in accordance withthe present invention, the first conduit means 62 has its lower end 66spaced slightly above the lowermost part of the formed lower end 72 ofthe second conduit means 68 to prevent water from passing up into thefirst conduit means 62 which is being utilized as a gas tube duringinitial filling of the humidifier 14. The lower end 66 is formed at anangle of 40 to 90 degrees to the longitudinal axis of the first conduitmeans, and preferably at an angle of 90 degrees.

As previously discussed, with reference to FIGS. 4-6 the clip 116engages against the flanges 94 and 102 of the first and second conduitmeans 62 and 68 and prevents the first and second conduit means 62 and68 from pulling out of the reservoir 16. In the event that one of theconduit means 62 or 68 would inadvertently become detached from thereservoir 16 during use of the system 10, there would be a massiveleakage of air into the reservoir 16 and passage of liquid out throughthe exposed associated opening 58 or 56. Also, there would be acontinuous stream of water through the remaining connected conduit means62 or 68 into the humidifier 14, and the ventilator 12 could pump partof the overfilled water in the humidifier 14 through the tube 114 intothe lungs of the patient, which might result in drowning of the patientor other harmful results. Thus, the clip 116 prevents harm to thepatient in the event that one of the conduit means 62 and 68 shouldotherwise become detached from the reservoir 16.

The foregoing detailed description is given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, as modifications will be obvious to those skilled in the art.

We claim:
 1. A feeding system, comprising:a humidifier; a reservoirhousing a liquid above the humidifier; first elongated conduit means forfeeding liquid from the reservoir to the humidifier and having an upperend and a lower end; second elongated conduit means alongside the firstconduit means for passing air from the humidifier to the reservoir andhaving an upper end and a lower end; means for connecting the upper endof the first and second conduit means in fluid communication to thereservoir below the level of liquid in the reservoir; and means forconnecting the conduit means to the upper part of the humidifier withthe lower end of the first and second conduit means located inside thehumidifier with the lower end of the first conduit means being locatedadjacent the lower end of the second conduit means, and with the lowerend of the first conduit means being located above at least a portion ofthe second conduit means and the lower end of the second conduit meansbeing cut off at a single angle through the second conduit meansrelative to the longitudinal axis of the second conduit means.
 2. Thesystem of claim 1 wherein the angle is approximately 45 degrees.
 3. Thesystem of claim 1 wherein the lowermost part of the lower end of thesecond conduit means is located adjacent the first conduit means.
 4. Thesystem of claim 1 wherein the angle is less than 60 degrees.
 5. Afeeding system, comprising:a humidifier; a reservoir housing a liquidabove the humidifier; first elongated conduit means for feeding liquidfrom the reservoir to the humidifier and having an upper end and a lowerend; second elongated conduit means alongside the first conduit meansfor passing air from the humidifier to the reservoir, and having anupper end and a lower end; means for connecting the upper end of thefirst and second conduit means in fluid communication to the reservoirbelow the level of liquid in the reservoir; and means for connecting theconduit means to the upper part of the humidifier with the lower end ofthe first and second conduit means located inside the humidifier, withthe lower end of the first conduit means being located adjacent thelower end of the second conduit means, and with at least a portion ofthe lower end of the second conduit means being located on one side ofand below the lower end of the first conduit means and the lower end ofthe second conduit means being formed at an angle relative to thelongitudinal axis of the second conduit means.
 6. The system of claim 5wherein the lower end of the first conduit means is formed at an angleof approximately 90 degrees to the longitudinal axis of the firstconduit means.
 7. The system of claim 5 wherein the lower end of thefirst conduit means is located intermediate the upper and lower portionof the angled lower end of the second conduit means.
 8. The system ofclaim 5 wherein the second conduit means is formed at an angle of from40 to 90 degrees to the longitudinal axis of the second conduit means.9. A feeding system, comprising:a humidifier having a bowl including anupper part and adapted to retain a supply of sterile liquid, heatingmeans, and a lid releasably attached to the upper part of the bowl, saidlid having a tubular section defining an outlet port of the humidifier;a reservoir located above the humidifier; first elongated conduit meansfor feeding liquid from the reservoir to the humidifier and having anupper end and a lower end; second elongated conduit means alongside thefirst conduit means for passing air from the humidifier to the reservoirand having an upper end and a lower end; means for connecting the upperend of the first and second conduit means in fluid communication to thereservoir; and a hollow first tube surrounding and closely spaced fromthe first and second conduit means, and a hollow second tube forming anangled extension of the first tube and in fluid communication with thefirst tube, said first tube being releasably attached to the lid tubularsection with the outlet port in fluid communication with the first tube,with a lower end portion of the first and second conduit means connectedto and extending through and from the first tube to a location insidethe humidifier, and the outside diameter of the first conduit meansbeing substantially smaller than the outside diameter of the secondconduit means.
 10. The system of claim 9 wherein the internal diameterof the first conduit means is approximately 0.080 inches, and theinternal diameter of the second conduit means is approximately 0.260inches.
 11. The system of claim 9 wherein the internal diameter of thefirst part of the elbow is approximately 0.730 inches.